Just to pile on:
Markets are efficient. Individuals behave rationally. All information is reflected in prices. Huh…are you kidding me? These are the beliefs held by traditional free market economists (“rationalists”) like Eugene Fama (Economist at the University of Chicago and a.k.a. the “Father of the Efficient Market Hypothesis”). Striking blows to the rationalists are being thrown by “behavioralists” like Richard Thaler (Professor of Behavioral Science and Economics at the University of Chicago), who believes emotions often lead to suboptimal decisions and also thinks efficient market economics is a bunch of hogwash.
"It's tough to make predictions, especially when it involves the future." ~Attributed to many
"In theory, there is no difference between theory and practice. But, in practice, there is." ~(perhaps by) Yogi Berra
"Those who have knowledge, don't predict. Those who predict, don't have knowledge."~ Lau tzu